The massive explosion that rocked the Middle Eastern city of Beirut in August, killing several hundred people and injuring thousands more happened when a fire broke out at a seaport warehouse. It ignited more than 3,000 tons of ammonium nitrate haphazardly stored nearby and damaged buildings as far as five miles away.
When such an unthinkable tragedy happens, the conversation inevitably turns to what could have been done differently to reduce casualties. In the aftermath, everyone wants to establish how to prevent such a disaster from ever occurring again. While no known technology can guarantee no damage to a building in an explosion, there are a few methods and materials in use today that can help minimize injury and loss of life.
Securing the Building Envelope
When an explosion goes off inside or near a building, shards of glass, metal, and cement wind up flying through the air. According to Peter DiMaggio, co-CEO at Thornton Tomasetti, these are the source of most fatalities in such an event. When building materials disintegrate from the force of the blast, it produces “secondary fragments.” The amount of these fragments can be reduced by fortifying the building envelope to contain debris better.
One such method is by reinforcing structural components and building facades with a special steel-reinforced concrete called DUCON, produced by Maryland-headquartered Structural Technologies. DUCON’s micro-reinforced concrete systems use a combination of high-strength, high-performance grout with a densely layered “MicroMat” steel reinforcement. The resulting structural concrete is more durable than traditional concrete. Architect Magazine writes DUCON is better able to withstand ballistic or other impacts, with a tensile strength up to 2,000 psi.
The DUCON system works by allowing energy to dissipate more efficiently in the event of a sudden impact. The system is extremely versatile and can be applied to new and existing buildings; it can even be prefabricated offsite.
Keeping Glass Intact After a Blast
Glass fragments propelled by an explosion are an obvious source of danger. Multiple manufacturers are producing special glass with blast-resistant glazing. Most of the designs involve adding a sturdy plastic layer inside or outside of the glass to help keep shards from flying apart.
Oldcastle BuildingEnvelope is a company producing a laminated blast-resistant glass, created with potential bomb targets in mind. A plastic interlayer keeps the glass from shattering after impact, and a specially designed frame keeps the damaged window in place. The glass is available in a variety of styles, colors, and thicknesses. It is already being used in various high-profile buildings like the Gateway Arch Grounds and Museum in St. Louis and the Ballet Memphis in Memphis, Tennessee.
Reinforced Steel Stud Walls
Steel stud construction has long been the standard for exterior walls for steel-framed buildings thanks to its relatively low cost and high flexibility. However, it does almost nothing to withstand the force of an explosion. One solution is the SEB wall, built by Simpson Gumpertz & Heger (SGH) with funding and assistance from the U.S. Army Research Laboratory and the U.S. Air Force Research Laboratory.
The result of the collaboration is a low-cost composite steel-sheathed stud wall system capable of withstanding major blasts without sending debris into areas containing people. Placing Sure-Board panels made of sheet steel and reinforced cement board on both sides of wall studs helps achieve a greatly improved blast resistance at a significantly lower cost than other comparable blast-resistant reinforcement systems.
“With a total construction cost of $27 per square foot (including materials and labor and excluding architectural finishes), it provides approximately 30% in cost savings in comparison to other high-performance blast-mitigating wall systems, including reinforced concrete, reinforced masonry, and precast/pre-stressed wall panels,” the SGH engineers wrote in Architect Magazine.
The interest in blast-resistant construction and materials took off after 9/11. There has been two decades of research and development to bring the technology to the point it’s at today. Many of the systems described above are deployed on sensitive public or government buildings that are still potential terror strike targets. However, the Beirut blast shows that sometimes the location of an explosion is harder to predict.
Naturally, fortifying a structure to withstand an explosion is more costly than traditional construction, but it’s a small price to pay when considering the lives that could be saved in the event of a disaster.